LIGO-G0900597-v1

Keith Riles

University of Michigan

LIGO Scientific Collaboration

International Conference

on Topics in Astroparticle

and Underground Physics

Rome – July 1, 2009

The Present

Gravitational Wave

Detection Effort

1

!"#$%#&'%(&#)*$#$*+,#-%!#)'./%

•! (&#)*$#$*+,#-%!#)'.%0%12*33-'.%*,%.3#4'5$*6'7%

•! 8'&$9&:#$*+,%3&+3#;#$*+,%.*6*-#&%$+%-*;"$%<+:'=.%.#6'%>#)'%'?9#$*+,@A%

–! !"#$%&%'(#)*+$,,-*.*/*

–! 01#*'"%)+2,"+,*$#3%"(4%'(#)+*5*67%-"7$#3%"8*****9**%)-**:**

2

Example:"

Ring of test masses"

responding to wave"

propagating along z"

Amplitude parameterized by (tiny) !

! dimensionless strain h: !L ~ h(t) x L!

!"=%-++B%C+&%(&#)*$#$*+,#-%2#D*#$*+,/%

•! ;,/%7+,*('<+*'=,",>*?$",+7@%A3BC*

•! 0,+'*D,),"%3*E,3%'(2('B8*–!F7%-"7$#3%"*"%-(%'(#)G*0"%2,3+*%'*+$,,-*#H*3(&='G*

–!I)(67,*$"#A,*#H*+'"#)&5H(,3-*&"%2('B*

•! D%()*-(HH,",)'*2(,1*#H*I)(2,"+,8*

–! J#7"/,+*/%))#'*A,*#A+/7",-*AB*-7+'*K*+',33%"*,)2,3#$,+*

–!L,',/'%A3,*+#7"/,+*+#@,*#H*'=,*@#+'*()',",+'()&M**

* 3,%+'*7)-,"+'##-*()*'=,*I)(2,"+,*

–!N$,)+*7$*,)'(",3B*),1*)#)5,3,/'"#@%&),'(/*+$,/'"7@*

3

!"#$%6*;"$%$"'%.B=%-++B%-*B'/%

4

!"#$%6#B'.%(&#)*$#$*+,#-%!#)'./%

•! E%-(%'(#)*&,),"%',-*AB*67%-"7$#3%"*@%++*@#2,@,)'+8*

*******?1('=*Iµ"*.*67%-"7$#3,*',)+#"M*"*.*+#7"/,*-(+'%)/,C*

•! O:%@$3,8*!%("*#H*PQR*S+#3%"*),7'"#)*+'%"+*()*/("/73%"*#"A('*#H*"%-(7+*TU*V@*?(@@(),)'*/#%3,+/,)/,C*%'*#"A('%3*H",67,)/B*RUU*W4*&(2,+*XUU*W4*"%-(%'(#)*#H*%@$3('7-,8*

5

Strong Indirect Evidence:

Binary Orbit Decay

Y,7'"#)*;()%"B*JB+',@*Z*W73+,*[*0%B3#"*

!JE*P\P]*9*P^**55*0(@()&*#H*$73+%"+*

6

•#

•#

17 / sec"

Neutron Binary System

•! separated by 106 miles •! m1 = 1.44m!; m2 = 1.39m!; $ = 0.617

Prediction from general relativity

•! spiral in by 3 mm/orbit

•! rate of change orbital period

~ 8 hr

Emission of gravitational waves

7

What makes Gravitational Waves?!

•! E+63#4$%:*,#&=%*,.3*&#-F% *!"#$%&'()

–! YJ5YJ*1%2,H#"@+*%",*1,33*-,+/"(A,-*–! E,/,)'*$"#&",++*#)*;W5;W*1%2,H#"@+****

•! G93'&,+)#'%H%(2I.F% * *!*+%','(**

–! A7"+'*+(&)%3+*()*/#()/(-,)/,*1('=*+(&)%3+*()*,3,/'"#@%&),'(/*"%-(%'(#)*K*),7'"()#+*

–! %335+VB*7)'"(&&,",-*+,%"/=,+*'##*

•! 89-.#&.%*,%+9&%;#-#J=F% *!&-%$./$"()

–! +,%"/=*H#"*#A+,"2,-*),7'"#)*+'%"+*****************–! %335+VB*+,%"/=*?/#@$7'()&*/=%33,)&,C*

•! E+.6+-+;*4#-%G*;,#-. ***!',."#0',$")*0"12%.+3/()

(&#)*$#$*+,#-%!#)'%K'$'4$*+,%

•! J7+$,)-,-*_)',"H,"#@,',"+*

–! J7+$,)-,-*@(""#"+*()*`H",,5H%33a*

–!S(/=,3+#)*_bN*(+**

* `)%'7"%3a*Dc*-,',/'#"*

–!;"#%-5A%)-*",+$#)+,*

****?dPU*W4*'#*H,1*VW4C*

–!c%2,H#"@*()H#"@%'(#)*

* ?,Q&QM*/=("$*",/#)+'"7/'(#)C*8

9

L"'%(-+:#-%M,$'&C'&+6'$'&%N'$>+&B%The three (two) LIGO, Virgo and GEO interferometers are part of a Global Network.

Multiple signal detections will increase detection confidence and provide better precision on

source locations and wave polarizations

LIGO GEO Virgo

TAMA

AIGO (proposed)

H1, H2

G1 L1

T1

V1

LIGO"

Livingston, Louisiana & Hanford,

Washington"

2 x 4000-m"

(1 x 2000-m)"

Completed 2-year data run at design sensitivity –

“enhancement” finishing"

VIRGO"

Near Pisa, Italy"1 x 3000-m"

Took ~4 months coincident data with LIGO –

approaching design sensitivity"

GEO"

Near Hannover, Germany" 1 x 600-m"

Took data during L-V downtime, about to

undergo upgrade"

TAMA"

Tokyo, Japan" 1 x 300-m"

Used for R&D aimed at future underground

detector"

10

S%e#"*_)',"H,"#@,',"+**1#"3-51(-,*

11

K#$#%29,. **

GO%&9,F**OP%D#=.%<Q9;%H%G'3$%RSSRA*Z*E#7&=*A7'*&##-*$"%/'(/,*

Have carried out a series of Engineering Runs (LIGO E1–E14, Virgo WSR 1-13) and

Science Runs (LIGO S1--S5, Virgo VSR1) interspersed with commissioning

S2 run: 59 days (Feb—April 2003) – Many good results

S3 run:

70 days (Oct 2003 – Jan 2004) -- Ragged

S4 run:

30 days (Feb—March 2005) – Another good run

S5 run: (VSR1 for Virgo)

23 months (Nov 2005 – Sept 2007) – At design sensitivity – focus of today

hrms = 3 10-22

f_DN*JP*!*Jg*J,)+('(2('(,+*

12

Strain

spectral noise density

13

Virgo Sensitivities

Black measurements – VSR1 – 2007

Red measurements – May 2009

Design !

Much better sensitivity than

LIGO below ~40 Hz !! Binary black holes

!! “Young” pulsars, e.g., Vela

J,%"/=()&*H#"*D"%2('B*c%2,+*

14

Binary Inspirals Continuous

waves

(NS-NS, NS-BH, BH-BH) (Spinning

NS)

Bursts Stochastic background

(Supernovae, “mergers”) (Cosmological,

astrophysical)

Long-Lived Short-Lived

Known

waveform

Unknown

waveform

Spinning black-hole / SGR ringdowns Young pulsars

high-mass inspirals (glitchy)

John Rowe, CSIRO

15

A week’s histogram:

If system is optimally located and oriented, we can

see even further: we are surveying hundreds of

galaxies

John Rowe, CSIRO

16

17

•! I+,*'1#*#"*@#",*-,',/'#"+8*+,%"/=*H#"*-#7A3,*#"*'"($3,*".$3"$/-3,*`'"(&&,"+a*

•! h%)*()H,"*@%++,+*%)-*`,HH,/'(2,a*-(+'%)/,Q**

•! O+'(@%',*()2,"+,*H%3+,*%3%"@*$"#A%A(3('B*#H**",+73'()&*/%)-(-%',+8*-,',/'(#)G*

John Rowe, CSIRO

S5 Year 1 Search for “Low-Mass” Inspirals

Blue – Coincident

Gray – Time lag

Triple Double Double

18

•! Y#*,2(-,)/,*#H*,:/,++*

•! I+,*-,',/'(#)*,HH(/(,)/B*%)-*+7"2,B,-*&%3%:(,+**

******!*J,'*7$$,"*3(@('*2+*+',33%"*@%++* ***

% 8"=.T%2')T%K%PU%<RSSUA%ORRSSO%

John Rowe, CSIRO

BH-BH NS-BH

L10 = 1010 ! blue solar luminosity

Milky Way = 1.7 L10

19

DE;*UiUTUP*

•! G"+&$V%"#&D%;#66#5&#=%:9&.$%

–! Q%-'#D*,;%6+D'-%C+&%."+&$%(2I.F%

:*,#&=%6'&;'&%*,)+-)*,;%#%

,'9$&+,%.$#&%

•! 8+.*$*+,%<C&+6%M8NA%4+,.*.$',$%>*$"%

:'*,;%*,%WXO%<Q,D&+6'D#A%

•! YM(Z%[O%#,D%[R%>'&'%+3'&#$*,;%

•! 2'.9-$%C&+6%<.')'&#-A%YM(Z%.'#&4"'.F%

N+%3-#9.*:-'%(!%.*;,#-%C+9,D\%

$"'&'C+&'%)'&=%9,-*B'-=%$+%:'%

C&+6%#%:*,#&=%6'&;'&%*,%WXO%

*******Q3T%]T%^_O%<RSS_A%O`OU%

%%%%%%!%Y*B'-=%>#.%G(2%;*#,$%C-#&'%*,%WXO%

IPN 3-sigma error region from Mazets et al., ApJ 680, 545

20

hRSS

S5 Year 1 Search for Untriggered Bursts

Sampling of efficiency curves:

"! Search for double or triple coincident triggers (three algorithms)

"! Check waveform consistency among interferometers – apply vetoes

"! Set a threshold for detection for low false alarm probability

"! Evaluate efficiency for variety of simple waveforms

Parameterize strength in terms of “root sum square of h” : hRSS

21

Detected triggers and

expected background for one algorithm (Coherent

WaveBurst – wavelet-based) for triple-coincident triggers

with fcentral > 200 Hz

Threshold

No candidates found above threshold

in any of the searches ! Set upper limits on rate vs hRSS

Coherent network amplitude arXiv:0905.0020 (May 2009)

22

h"%A*!73+%"*

Upper limits on GW strain amplitude h0

Single-template, uniform prior: 3.4 ! 10–25

Single-template, restricted prior: 2.7 ! 10–25

Multi-template, uniform prior: 1.7 ! 10–24

Multi-template, restricted prior: 1.3 ! 10–24

Chandra

im

age

Mod

el

Implies that GW

emission accounts for " 4% of total

spin-down power

Ap. J. Lett 683 (2008) 45

Use coherent, 9-month, time-domain matched filter Strain amplitude h0

Bayesian PDF

23

Same matched-filter algorithm applied to 116

known pulsars over 23 months of S5

PRELIMINARY

All-sky search for

unknown isolated

neutron stars

Semi-coherent,

stacks of 30-minute,

demodulated power

spectra

(“PowerFlux”)

Linearly polarized

Circularly polarized

24

Phys. Rev. Lett. 102 (2009) 111102

arXiv:0905.1705 (May 2009) 25

All-sky search for

unknown isolated

neutron stars

Coincidence

among multiple 30-

hour coherent

searches

(Einstein@Home)

26

•! DON5^UU*W%))#2,"**

•! f_DN*W%)H#"-*

•! f_DN*f(2()&+'#)*

•! h7"",)'*+,%"/=*$#()'*

•! h7"",)'*+,%"/=*/##"-()%',+*

•! j)#1)*$73+%"+*

•! j)#1)*+7$,")#2%,*",@)%)'+*

http://www.einsteinathome.org/

Your

computer

can help

too!

Improved

(hierarchical)

algorithm

now running

27

•! Q%3&*6+&D*#-%*.+$&+3*4%(!%.$+4"#.$*4%:#4B;&+9,D%*.%3&'D*4$'D%:=%6+.$%4+.6+-+;*4#-%$"'+&*'.T%%

•! (*)',%#,%','&;=%D',.*$=%.3'4$&96%%;><!AV%$"'&'%*.%#%.$&#*,%3+>'&%.3'4$&96F%%

•! L"'%.*;,#-%4#,%:'%.'#&4"'D%C&+6%4&+..54+&&'-#"#$%&'#%'(#!!)*)%"'+,#*&'$!'()")-"$*&.''/0120',%('201234''

•! L"'%C#&$"'&%$"'%D'$'4$+&.V%$"'%-+>'&%$"'%C&'?9',4*'.%%$"#$%4#,%:'%.'#&4"'DT%

NASA, WMAP

28

O%"3B5Jg*WP5fP*;%B,+(%)*\Uk*If8***

#90% = 9.0 ! 10-6 ?RT5Pii*W4C

NASA, WMAP

29

Search for Gravitational Wave Bursts from Soft Gamma Repeaters

Phys Rev Lett 101 (2008) 211102

Search for High Frequency Gravitational Wave Bursts in the First Calendar Year of LIGO's Fifth Science Run

arXiv:0904.4910

Stacked Search for Gravitational Waves from the 2006 SGR 1900+14 Storm

arXiv:0905.0005

Search for Gravitational Waves from Low Mass Compact Binary Coalescence in 186

Days of LIGO's fifth Science Run arXiv:0905.3710

30

Inspirals: High-mass, spinning black holes

Year 2, joint LIGO-Virgo Ringdowns

GRBs

Bursts: Year 2, Joint LIGO-Virgo

GRBs

Continuous wave: Full-S5 all-sky searches (semi-coherent, Einstein@Home)

Directed searches (Cassiopeia A, globular clusters, galactic center, SN1987A)

“Transient CW” sources All-sky binary

Stochastic: Full-S5 isotropic – imminent Directed (anisotropic)

H1-H2 High-frequency (37 kHz – LIGO arm free spectral range)

31

Y++B*,;%Q"'#D%

Both LIGO and Virgo underwent significant upgrades since last

science run:

Initial LIGO ! “Enhanced LIGO”

Initial Virgo ! “Virgo +”

Data taking resumes next week, but with significant commissioning

breaks scheduled to fix noise sources that sustained running reveals

!! Running/commissioning strategy worked very well for LIGO in S5

!! Aiming at up to factor of two improvement in strain sensitivity

(most feasible for higher frequencies)

Shutdown for installation of Advanced LIGO and Virgo – early 2011 (see presentation by G. Losurdo)

32

G'#&4"*,;%C+&%)'&=5-+>5C&'?9',4=%%

.$+4"#.$*4%;&#)*$=%>#)'.%a%%89-.#&%L*6*,;%Q&&#=.%

By precisely monitoring the timings of an array of many millisecond pulsars

in different directions, radio astronomers hope to detect direct evidence of stochastic gravitational waves

!! Look for quadrupolar pattern in solar

system timing residuals

Several groups:

Parkes Pulsar Timing Array (Australia)

European Pulsar Timing Array (U.K., France, Netherlands, Italy)

Nano-Grav (USA)

! Aiming to improve upon existing limit: !(nHz) ! 10-8

Eventual followup with proposed Square Kilometer Array (SKA)

! Aiming to reach !(nHz) ! 10-13

33

G966#&=%Bottom line:

No GW signal detected yet #

But

•! Not all S5 / VSR1 searches completed

•! Upcoming S6 / VSR2 searches should be more sensitive

•! Advanced LIGO / Virgo promise major sensitivity improvements with

orders of magnitude increase in expected event rates

And

•! Radio pulsars may provide alternative first glimpse of the elusive

graviton

34

Extra

Slides

35

YM(Z%Z:.'&)#$+&*'.%

Livingston

Hanford

Observation of nearly simultaneous signals

3000 km apart rules out terrestrial artifacts

36

b*&;+%

Have begun collaborating with Virgo colleagues (Italy/France)

Took data in coincidence for last ~4 months of latest science run

Data exchange and joint analysis underway

Will coordinate closely on detector upgrades and future data taking

3-km Michelson

Interferometer just

outside Pisa, Italy

37

(cZ^SS%

Work closely with the GEO600 Experiment (Germany / UK / Spain)

•! Arrange coincidence data runs when commissioning schedules permit

•! GEO members are full members of the LIGO Scientific Collaboration

•! Data exchange and strong collaboration in analysis now routine

•! Major partners in proposed Advanced LIGO upgrade

600-meter Michelson Interferometer

just outside Hannover, Germany

38

YM(Z%K'$'4$+&%d#4*-*$*'.%

b#4996%G=.$'6%

•!Stainless-steel tubes

(1.24 m diameter, ~10-8 torr)

•!Gate valves for optics isolation

•!Protected by concrete enclosure

39

YM(Z%K'$'4$+&%d#4*-*$*'.%YQGc2%

•! M,C&#&'D%<OS^`%,6V%OS5!A%ND5eQ(%-#.'&%C&+6%Y*;"$>#)'%<,+>%4+66'&4*#-%3&+D94$@A%

•! c-#:+&#$'%*,$',.*$=%f%C&'?9',4=%.$#:*-*g#$*+,%.=.$'6V%*,4-9D*,;%C''D:#4B%C&+6%6#*,%*,$'&C'&+6'$'&%

Z3$*4.%

•! d9.'D%.*-*4#%<"*;"5hV%-+>5#:.+&3$*+,V%O%,6%.9&C#4'%&6.V%Ri546%D*#6'$'&A%

•! G9.3',D'D%:=%.*,;-'%.$''-%>*&'%

•! Q4$9#$*+,%+C%#-*;,6',$%H%3+.*$*+,%)*#%6#;,'$.%f%4+*-.%%

40

YM(Z%K'$'4$+&%d#4*-*$*'.%G'*.6*4%M.+-#$*+,%•! W9-$*5.$#;'%<6#..%f%.3&*,;.A%+3$*4#-%$#:-'%.933+&$%;*)'.%OS^%.933&'..*+,%

•! 8',D9-96%.9.3',.*+,%;*)'.%#DD*$*+,#-%O%H%C%R%.933&'..*+,%#:+)'%jO%[g%

102

100

10-2

10-4

10-6

10-8

10-10

Horizontal

Vertical

10-6

41

f_DN*_)',"H,"#@,',"*N$'(/%3*

J/=,@,*

end test mass

LASER/MC

6W

recycling

mirror

•!Recycling mirror matches losses,

enhances effective power by ~ 50x

150 W

20000 W (~0.5W)

Michelson interferometer

4 km Fabry-Perot cavity

With Fabry-Perot arm cavities

42

!"#$%Y*6*$.%$"'%G',.*$*)*$=%

+C%$"'%M,$'&C'&+6'$'&./*%l! G'*.6*4%,+*.'%f%)*:&#$*+,%-*6*$%#$%

-+>%C&'?9',4*'.%

l! Q$+6*4%)*:&#$*+,.%<L"'&6#-%N+*.'A%*,.*D'%4+63+,',$.%-*6*$%#$%6*D%C&'?9',4*'.%

l! h9#,$96%,#$9&'%+C%-*;"$%<G"+$%N+*.'A%-*6*$.%#$%"*;"%C&'?9',4*'.%

l! W=&*#D%D'$#*-.%+C%$"'%-#.'&.V%'-'4$&+,*4.V%'$4TV%4#,%6#B'%3&+:-'6.%#:+)'%$"'.'%-')'-.%

Best design sensitivity:

~ 3 x 10-23 Hz-1/2 @ 150 Hz

43

“Locking” the Interferometer

Sensing gravitational waves requires sustained resonance in the Fabry-Perot arms and in the

recycling cavity

!! Need to maintain half-integer # of laser wavelengths between mirrors

!! Feedback control servo uses error signals from imposed RF sidebands

!! Four primary coupled degrees of freedom to control

!! Highly non-linear system with 5-6 orders of magnitude in light intensity

Also need to control mirror rotation (“pitch” & “yaw”)

!! Ten more DOF’s (but less coupled)

And need to stabilize laser (intensity & frequency), keep the beam pointed, damp out seismic

noise, correct for tides, etc.,…